Dealing with colleagues talking to me but not facng me directly

Another personality development thread. :)

So, do we actually have a verb for such act? someone talking to me, about me but not facing me directly. The incidents are like this.

There is this colleague of mine and whenever there is a conversation, or most of the times, when it revolves around me, he/she tends to face other person and speak about me. The intentions are crystal clear - venting out, making fun of me, taunting me. I am really not sure if they speak about me in my absence, but I always think that if I am around and I am the topic of conversation, why not face me directly. And most of the times, what I say also goes into thin air for whatever reason. They are more loud.

or there could be a topic which I am not well versed with, so I keep mum. And one goody goody colleague says, "why don't you talk something??" and next comes a conversation which I can talk about and when I do that the same colleague is making long faces and kinda taunts or pokes. But since I can talk about that topic I can easily vanish that taunt by another taunt/fact and that keeps them mum. But that kinda increases the rift. I cannot afford to see those long, sulking faces.

Gawd.. I am desperately trying to improve myself and need a solution to all such incidents.

Dealing with colleagues talking to me but not facng me directly